1) Field of the Invention
This invention relates to the secondary conductor of an elevator-driving linear induction motor.
2) Description of Related Art
The co-pending prior U.S. application Ser. No. 07/953,710 discloses an arrangement of the secondary conductor of an elevator-driving linear induction motor employable for a linear-motor-driven elevator as shown in FIGS. 12 and 13.
In FIGS. 12 and 13, reference numeral 1 designates walls of an elevating shaft; 2, secondary conductors of a linear induction motor which are mounted on the walls 1 of the elevating shaft; 3, brackets for fixedly mounting the secondary conductors 2 on the elevating shaft walls; 4, primary windings of the motor which confront with the secondary conductors 2, to cause the linear induction motor to generate a driving force; 5, U-shaped primary winding supports each supporting a pair of primary windings 4 which are confronted with each other through the secondary conductor 2; 6, an elevator driver on which a plurality of primary winding supports 5 are mounted; and 9, the connecting sections of the secondary conductor members which are connected in series to one another in the direction of movement of the elevator.
Further in FIGS. 12 and 13, reference numeral 10 designates a cage for transporting passengers; 13, a rope connected between the cage 10 and the elevator driver 6 to transmit the driving force from the latter 6 to the former 10; and 11 and 12, sheaves which receives the weight of the cage 10 and the weight of the driver 6 through the rope 13 and change the direction of tension of the rope 13.
FIGS. 14(a) and 14(b) are a perspective view and a sectional view, respectively, showing the connecting portions 9 of the secondary conductors 2. In FIGS. 14(a) and 14(b), reference numeral 8 designates bolts which are used to fixedly secure the secondary conductors 2 to the mounting bracket 3.
In the linear-induction-motor-driven elevator designed as described above, the cage is driven as follows: When current is supplied from a drive control unit (not shown) to the primary windings 4 confronted with one another, shifting magnetic field are produced in a direction perpendicular to the surface of the drawing FIG. 13. The shifting magnetic fields thus produced are applied to the secondary conductors 2 located between the primary windings 4, to induce induction eddy currents. The interaction of the eddy currents thus induced and the shifting magnetic fields produces a driving force to drive the elevator cage 10 with the aid of the driver 6 and the rope 13.
In the case where the secondary conductors of the linear induction motor are longitudinally laid over the walls of the elevating shaft with their connecting portions engaged with one another, the secondary conductors must be positively connected to one another; otherwise, the secondary conductors, being bent for instance, are raised forming steps which contact or strike the primary windings. In this case, both the secondary conductors and the primary windings may be damaged.